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https://github.com/SEPPDROID/Digital-Research-Source-Code.git
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68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
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/****************************************************************
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* *
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* P-CP/M BDOS Disk I/O System Module *
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* *
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* This module translates from the packet oriented I/O *
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* passed from the other BDOS modules into BIOS calls. *
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* *
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* It includes only one external entry point: *
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* do_phio() - do physical i/o *
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* *
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* *
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* Modified for memory management on Z8000 *
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* *
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****************************************************************/
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#include "stdio.h" /* Standard I/O declarations */
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#include "bdosdef.h" /* Type and structure declarations for BDOS */
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#include "pktio.h" /* Packet I/O definitions */
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#include "biosdef.h" /* Declarations for BIOS entry points */
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EXTERN udiv(); /* Assembly language unsigned divide routine */
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/* in bdosif.s. It's used because Alcyon C */
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/* can't do / or % without an external */
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/************************
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* do_phio entry point *
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************************/
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UWORD do_phio(iop)
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REG struct iopb *iop; /* iop is a pointer to a i/o parameter block */
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{
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MLOCAL UBYTE last_dsk; /* static variable to tell which disk
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was last used, to avoid disk selects */
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REG struct dph *hdrp; /* pointer to disk parameter header */
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REG struct dpb *dparmp; /* pointer to disk parameter block */
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REG UWORD rtn; /* return parameter */
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UWORD iosect; /* sector number returned from divide rtn */
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LOCK /* lock the disk system while doing physical i/o */
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rtn = 0;
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switch (iop->iofcn)
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{
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case sel_info:
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iop->infop = bseldsk(last_dsk, iop->ioflags);
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break;
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case read:
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hdrp = iop->infop;
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dparmp = hdrp->dpbp;
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bsettrk( udiv( iop->devadr, dparmp->spt, (long)&iosect )
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+ dparmp->trk_off );
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bsetsec( bsectrn( iosect, hdrp->xlt ) );
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bsetdma(iop->xferadr);
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return(bread());
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}
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UNLOCK
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return(0);
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}
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